#ifndef UNIVERSAL_REALTIME_LIGHTS_INCLUDED
#define UNIVERSAL_REALTIME_LIGHTS_INCLUDED
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/AmbientOcclusion.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Input.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Shadows.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/LightCookie/LightCookie.hlsl"
#include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Clustering.hlsl"
///////////////////////////////////////////////////////////////////////////////
// Light Layers /
///////////////////////////////////////////////////////////////////////////////
// Note: we need to mask out only 8bits of the layer mask before encoding it as otherwise any value > 255 will map to all layers active if save in a buffer
uint GetMeshRenderingLightLayer()
{
#ifdef _LIGHT_LAYERS
return (asuint(unity_RenderingLayer.x) & RENDERING_LIGHT_LAYERS_MASK) >> RENDERING_LIGHT_LAYERS_MASK_SHIFT;
#else
return DEFAULT_LIGHT_LAYERS;
#endif
}
// Abstraction over Light shading data.
struct Light
{
half3 direction;
half3 color;
float distanceAttenuation; // full-float precision required on some platforms
half shadowAttenuation;
uint layerMask;
};
// WebGL1 does not support the variable conditioned for loops used for additional lights
#if !defined(_USE_WEBGL1_LIGHTS) && defined(UNITY_PLATFORM_WEBGL) && !defined(SHADER_API_GLES3)
#define _USE_WEBGL1_LIGHTS 1
#define _WEBGL1_MAX_LIGHTS 8
#else
#define _USE_WEBGL1_LIGHTS 0
#endif
#if USE_CLUSTERED_LIGHTING
#define LIGHT_LOOP_BEGIN(lightCount) \
ClusteredLightLoop cll = ClusteredLightLoopInit(inputData.normalizedScreenSpaceUV, inputData.positionWS); \
while (ClusteredLightLoopNextWord(cll)) { while (ClusteredLightLoopNextLight(cll)) { \
uint lightIndex = ClusteredLightLoopGetLightIndex(cll);
#define LIGHT_LOOP_END } }
#elif !_USE_WEBGL1_LIGHTS
#define LIGHT_LOOP_BEGIN(lightCount) \
for (uint lightIndex = 0u; lightIndex < lightCount; ++lightIndex) {
#define LIGHT_LOOP_END }
#else
// WebGL 1 doesn't support variable for loop conditions
#define LIGHT_LOOP_BEGIN(lightCount) \
for (int lightIndex = 0; lightIndex < _WEBGL1_MAX_LIGHTS; ++lightIndex) { \
if (lightIndex >= (int)lightCount) break;
#define LIGHT_LOOP_END }
#endif
///////////////////////////////////////////////////////////////////////////////
// Attenuation Functions /
///////////////////////////////////////////////////////////////////////////////
// Matches Unity Vanila attenuation
// Attenuation smoothly decreases to light range.
float DistanceAttenuation(float distanceSqr, half2 distanceAttenuation)
{
// We use a shared distance attenuation for additional directional and puctual lights
// for directional lights attenuation will be 1
float lightAtten = rcp(distanceSqr);
float2 distanceAttenuationFloat = float2(distanceAttenuation);
#if SHADER_HINT_NICE_QUALITY
// Use the smoothing factor also used in the Unity lightmapper.
half factor = half(distanceSqr * distanceAttenuationFloat.x);
half smoothFactor = saturate(half(1.0) - factor * factor);
smoothFactor = smoothFactor * smoothFactor;
#else
// We need to smoothly fade attenuation to light range. We start fading linearly at 80% of light range
// Therefore:
// fadeDistance = (0.8 * 0.8 * lightRangeSq)
// smoothFactor = (lightRangeSqr - distanceSqr) / (lightRangeSqr - fadeDistance)
// We can rewrite that to fit a MAD by doing
// distanceSqr * (1.0 / (fadeDistanceSqr - lightRangeSqr)) + (-lightRangeSqr / (fadeDistanceSqr - lightRangeSqr)
// distanceSqr * distanceAttenuation.y + distanceAttenuation.z
half smoothFactor = half(saturate(distanceSqr * distanceAttenuationFloat.x + distanceAttenuationFloat.y));
#endif
return lightAtten * smoothFactor;
}
half AngleAttenuation(half3 spotDirection, half3 lightDirection, half2 spotAttenuation)
{
// Spot Attenuation with a linear falloff can be defined as
// (SdotL - cosOuterAngle) / (cosInnerAngle - cosOuterAngle)
// This can be rewritten as
// invAngleRange = 1.0 / (cosInnerAngle - cosOuterAngle)
// SdotL * invAngleRange + (-cosOuterAngle * invAngleRange)
// SdotL * spotAttenuation.x + spotAttenuation.y
// If we precompute the terms in a MAD instruction
half SdotL = dot(spotDirection, lightDirection);
half atten = saturate(SdotL * spotAttenuation.x + spotAttenuation.y);
return atten * atten;
}
///////////////////////////////////////////////////////////////////////////////
// Light Abstraction //
///////////////////////////////////////////////////////////////////////////////
Light GetMainLight()
{
Light light;
light.direction = half3(_MainLightPosition.xyz);
#if USE_CLUSTERED_LIGHTING
light.distanceAttenuation = 1.0;
#else
light.distanceAttenuation = unity_LightData.z; // unity_LightData.z is 1 when not culled by the culling mask, otherwise 0.
#endif
light.shadowAttenuation = 1.0;
light.color = _MainLightColor.rgb;
#ifdef _LIGHT_LAYERS
light.layerMask = _MainLightLayerMask;
#else
light.layerMask = DEFAULT_LIGHT_LAYERS;
#endif
return light;
}
Light GetMainLight(float4 shadowCoord)
{
Light light = GetMainLight();
light.shadowAttenuation = MainLightRealtimeShadow(shadowCoord);
return light;
}
Light GetMainLight(float4 shadowCoord, float3 positionWS, half4 shadowMask)
{
Light light = GetMainLight();
light.shadowAttenuation = MainLightShadow(shadowCoord, positionWS, shadowMask, _MainLightOcclusionProbes);
#if defined(_LIGHT_COOKIES)
real3 cookieColor = SampleMainLightCookie(positionWS);
light.color *= cookieColor;
#endif
return light;
}
Light GetMainLight(InputData inputData, half4 shadowMask, AmbientOcclusionFactor aoFactor)
{
Light light = GetMainLight(inputData.shadowCoord, inputData.positionWS, shadowMask);
#if defined(_SCREEN_SPACE_OCCLUSION) && !defined(_SURFACE_TYPE_TRANSPARENT)
if (IsLightingFeatureEnabled(DEBUGLIGHTINGFEATUREFLAGS_AMBIENT_OCCLUSION))
{
light.color *= aoFactor.directAmbientOcclusion;
}
#endif
return light;
}
// Fills a light struct given a perObjectLightIndex
Light GetAdditionalPerObjectLight(int perObjectLightIndex, float3 positionWS)
{
// Abstraction over Light input constants
#if USE_STRUCTURED_BUFFER_FOR_LIGHT_DATA
float4 lightPositionWS = _AdditionalLightsBuffer[perObjectLightIndex].position;
half3 color = _AdditionalLightsBuffer[perObjectLightIndex].color.rgb;
half4 distanceAndSpotAttenuation = _AdditionalLightsBuffer[perObjectLightIndex].attenuation;
half4 spotDirection = _AdditionalLightsBuffer[perObjectLightIndex].spotDirection;
#ifdef _LIGHT_LAYERS
uint lightLayerMask = _AdditionalLightsBuffer[perObjectLightIndex].layerMask;
#else
uint lightLayerMask = DEFAULT_LIGHT_LAYERS;
#endif
#else
float4 lightPositionWS = _AdditionalLightsPosition[perObjectLightIndex];
half3 color = _AdditionalLightsColor[perObjectLightIndex].rgb;
half4 distanceAndSpotAttenuation = _AdditionalLightsAttenuation[perObjectLightIndex];
half4 spotDirection = _AdditionalLightsSpotDir[perObjectLightIndex];
#ifdef _LIGHT_LAYERS
uint lightLayerMask = asuint(_AdditionalLightsLayerMasks[perObjectLightIndex]);
#else
uint lightLayerMask = DEFAULT_LIGHT_LAYERS;
#endif
#endif
// Directional lights store direction in lightPosition.xyz and have .w set to 0.0.
// This way the following code will work for both directional and punctual lights.
float3 lightVector = lightPositionWS.xyz - positionWS * lightPositionWS.w;
float distanceSqr = max(dot(lightVector, lightVector), HALF_MIN);
half3 lightDirection = half3(lightVector * rsqrt(distanceSqr));
// full-float precision required on some platforms
float attenuation = half(DistanceAttenuation(distanceSqr, distanceAndSpotAttenuation.xy) * AngleAttenuation(spotDirection.xyz, lightDirection, distanceAndSpotAttenuation.zw));
Light light;
light.direction = lightDirection;
light.distanceAttenuation = attenuation;
light.shadowAttenuation = 1.0; // This value can later be overridden in GetAdditionalLight(uint i, float3 positionWS, half4 shadowMask)
light.color = color;
light.layerMask = lightLayerMask;
return light;
}
uint GetPerObjectLightIndexOffset()
{
#if USE_STRUCTURED_BUFFER_FOR_LIGHT_DATA
return uint(unity_LightData.x);
#else
return 0;
#endif
}
// Returns a per-object index given a loop index.
// This abstract the underlying data implementation for storing lights/light indices
int GetPerObjectLightIndex(uint index)
{
/////////////////////////////////////////////////////////////////////////////////////////////
// Structured Buffer Path /
// /
// Lights and light indices are stored in StructuredBuffer. We can just index them. /
// Currently all non-mobile platforms take this path :( /
// There are limitation in mobile GPUs to use SSBO (performance / no vertex shader support) /
/////////////////////////////////////////////////////////////////////////////////////////////
#if USE_STRUCTURED_BUFFER_FOR_LIGHT_DATA
uint offset = uint(unity_LightData.x);
return _AdditionalLightsIndices[offset + index];
/////////////////////////////////////////////////////////////////////////////////////////////
// UBO path /
// /
// We store 8 light indices in half4 unity_LightIndices[2]; /
// Due to memory alignment unity doesn't support int[] or float[] /
// Even trying to reinterpret cast the unity_LightIndices to float[] won't work /
// it will cast to float4[] and create extra register pressure. :( /
/////////////////////////////////////////////////////////////////////////////////////////////
#elif !defined(SHADER_API_GLES)
// since index is uint shader compiler will implement
// div & mod as bitfield ops (shift and mask).
// TODO: Can we index a float4? Currently compiler is
// replacing unity_LightIndicesX[i] with a dp4 with identity matrix.
// u_xlat16_40 = dot(unity_LightIndices[int(u_xlatu13)], ImmCB_0_0_0[u_xlati1]);
// This increases both arithmetic and register pressure.
//
// NOTE: min16float4 bug workaround.
// Take the "vec4" part into float4 tmp variable in order to force float4 math.
// It appears indexing half4 as min16float4 on DX11 can fail. (dp4 {min16f})
float4 tmp = unity_LightIndices[index / 4];
return int(tmp[index % 4]);
#else
// Fallback to GLES2. No bitfield magic here :(.
// We limit to 4 indices per object and only sample unity_4LightIndices0.
// Conditional moves are branch free even on mali-400
// small arithmetic cost but no extra register pressure from ImmCB_0_0_0 matrix.
half indexHalf = half(index);
half2 lightIndex2 = (indexHalf < half(2.0)) ? unity_LightIndices[0].xy : unity_LightIndices[0].zw;
half i_rem = (indexHalf < half(2.0)) ? indexHalf : indexHalf - half(2.0);
return int((i_rem < half(1.0)) ? lightIndex2.x : lightIndex2.y);
#endif
}
// Fills a light struct given a loop i index. This will convert the i
// index to a perObjectLightIndex
Light GetAdditionalLight(uint i, float3 positionWS)
{
#if USE_CLUSTERED_LIGHTING
int lightIndex = i;
#else
int lightIndex = GetPerObjectLightIndex(i);
#endif
return GetAdditionalPerObjectLight(lightIndex, positionWS);
}
Light GetAdditionalLight(uint i, float3 positionWS, half4 shadowMask)
{
#if USE_CLUSTERED_LIGHTING
int lightIndex = i;
#else
int lightIndex = GetPerObjectLightIndex(i);
#endif
Light light = GetAdditionalPerObjectLight(lightIndex, positionWS);
#if USE_STRUCTURED_BUFFER_FOR_LIGHT_DATA
half4 occlusionProbeChannels = _AdditionalLightsBuffer[lightIndex].occlusionProbeChannels;
#else
half4 occlusionProbeChannels = _AdditionalLightsOcclusionProbes[lightIndex];
#endif
light.shadowAttenuation = AdditionalLightShadow(lightIndex, positionWS, light.direction, shadowMask, occlusionProbeChannels);
#if defined(_LIGHT_COOKIES)
real3 cookieColor = SampleAdditionalLightCookie(lightIndex, positionWS);
light.color *= cookieColor;
#endif
return light;
}
Light GetAdditionalLight(uint i, InputData inputData, half4 shadowMask, AmbientOcclusionFactor aoFactor)
{
Light light = GetAdditionalLight(i, inputData.positionWS, shadowMask);
#if defined(_SCREEN_SPACE_OCCLUSION) && !defined(_SURFACE_TYPE_TRANSPARENT)
if (IsLightingFeatureEnabled(DEBUGLIGHTINGFEATUREFLAGS_AMBIENT_OCCLUSION))
{
light.color *= aoFactor.directAmbientOcclusion;
}
#endif
return light;
}
int GetAdditionalLightsCount()
{
#if USE_CLUSTERED_LIGHTING
// Counting the number of lights in clustered requires traversing the bit list, and is not needed up front.
return 0;
#else
// TODO: we need to expose in SRP api an ability for the pipeline cap the amount of lights
// in the culling. This way we could do the loop branch with an uniform
// This would be helpful to support baking exceeding lights in SH as well
return int(min(_AdditionalLightsCount.x, unity_LightData.y));
#endif
}
half4 CalculateShadowMask(InputData inputData)
{
// To ensure backward compatibility we have to avoid using shadowMask input, as it is not present in older shaders
#if defined(SHADOWS_SHADOWMASK) && defined(LIGHTMAP_ON)
half4 shadowMask = inputData.shadowMask;
#elif !defined (LIGHTMAP_ON)
half4 shadowMask = unity_ProbesOcclusion;
#else
half4 shadowMask = half4(1, 1, 1, 1);
#endif
return shadowMask;
}
#endif